Implementing Green Roofs in the Private Realm for City-Wide Stormwater Management in Vancouver: Lessons Learned from Toronto and Portland

Abstract

Green roofs are an innovative stormwater management technology that has numerous environmental benefits. Citywide implementation is critical to maximizing the benefits of green roofs, especially in terms of jurisdictional encouragement and advancing management programs. The City of Vancouver is interested in developing a rainwater management strategy that supports the widespread implementation of green roofs on private property. Performance control for a green roof on private property requires standards on local natural factors that affect performance; development considerations; supporting legal tools; maintenance and operation responsibilities; equity through the different types of private properties; and finally, cost. Research into the rainwater management strategies for the cities of Toronto and Portland for green roof implementation was conducted to provide insight into the best approaches for such an implementation in Vancouver. Portland and Toronto both have independent green roof standards in addition to separate rainwater management strategies. Portland focuses on a post-occupancy inspection program to monitor a green roof’s ongoing performance, while Toronto established the Green Roof Bylaw to encourage the implementation of green roofs. Incentive programs that educate and encourage private owners to take the initiative to construct and effectively operate green roofs are essential to the success of a private green roof program.